The FOSIT (Fosamax International Trial) was a placebo-controlled, double blind trial, to determine the effects of daily oral dose of 10 mg alendronate-sodium (Fosamax) or placebo, for one year in postmenopausal osteoporotic women. It was an international, multicenter study; the 153 centers distributed over 34 countries. The number of patients was 1908. Authors report the data of the only Hungarian study site, Debrecen. Twenty women [age (mean +/- SD) 62 +/- 8 years with bone mineral density--BMD--< or = 0.98 g/cm2 at the lumbar spine by LUNAR DPX densitometer] were enrolled into the study and randomly assigned to oral alendronate 10 mg daily or placebo (10 patients in each group). Patients in both groups received 500 mg of calcium. Bone density measurements were performed by dual x-ray absorptiometry (DXA) at months 0, 3, 6, and 12 at the lumbar spine and at the femoral neck. Biochemical indices of bone turnover [bone specific alkaline phosphatase (bAP) and urinary N-telopeptide/creatinine ratio (NTx/crea] were also measured every three months. Percent change of the BMD measurements from baseline at one-year in the alendronate group was +6% and in the placebo group -0.7% on the lumbar spine (p < 0.001). Alendronate treatment increased the bone mineral density in the femoral neck, the trochanter, the Ward's triangle and the total hip by +3.2, +1.6, +3.5, +2.2% respectively, meanwhile the changes in the placebo group were -1.2%; -0.7%; -0.9%; -0.8%, respectively, the difference was not significant. Urinary NTx/crea decreased by 70.6% in the alendronate group and by 9.4% in the placebo group, while bAP decreased by 47.4% in the alendronate group and 15.2% in the placebo group (p < 0.001). In conclusion, after one year of treatment with alendronate induced increase of bone mineral density at the lumbar spine and decreased the bone turnover as compared to the placebo group.